#5499 could mesangial c3 deposition be an independent prognostic marker in immunoglobulin a nephropathy?

Abstract Background and Aims Immunoglobulin A nephropathy (IgAN) is a common primary glomerulonephropathy and the role of complement activation in the pathogenesis has not been fully clarified. There is evidence that mesangial C3 deposition plays a role in the development of the disease. The aim of this study was to examine the effect of C3 deposition on the prognosis of IgAN patients. Method The study included 1135 patients with IgAN confirmed by biopsy using the datatbase of the Turkish Nephrology Association Glomerular Diseases Working Group (TSN-GOLD). Patients were excluded from the study if they were aged <18 or >75 years, or if C3 staining had not been performed in the immunofluorescent analysis. C3 deposition was defined as immunofluorescent staining within the mesangium as 1+ negative and no staining, and 2+ and 3+ positive intensity staining (<2+ and ≥2+). Evaluation was also made according to the Oxford MEST-C classification. The primary endpoint was the development of end-stage renal failure (ESRF), and kidney transplantation, and an increase of 30% in glomerular filtration rate (GFR) compared to the basal value, or an elevation in proteinuria to a nephrotic level (3.5 gr/day) were accepted as poor prognosis. Results Mesangial C3 deposition was determined in 603 (53.1%) patients. In the evaluation of basal values between the groups with and without deposition, no statistically significant difference was determined in respect of age, gender, BMI, proteinuria level, or the presence of hypertension. In the follow-up period of mean 78 months survival, no significant difference was determined between the two groups in respect of the primary endpoint (C3+:53.1% vs. C3-:46.9%, p = 0.43). A significant correlation was determined between C3 deposition and segmental glomerulosclerosis (S1) according to the Oxford MEST-C classification (p = 0.001). Conclusion Although a correlation was seen between mesangial C3 deposition and the S1 MEST-C classification, the use of these alone or together as a prognostic factor in IgAN is not appropriate.